11:00 - 12:30
Parallel sessions 2
11:00 - 12:30
Room: HSZ - N5
Chair/s:
Volker H. Franz, Rolf Ulrich
We examine recent advances in the psychophysical investigation of cognitive representations and mechanisms. The overarching question is how we can use psychophysical measurement to learn something about the cognitive representations and their functional relevance in the human mind. We will investigate questions in the domains of time and size perception as well as motion prediction and will apply advanced psychophysical methods to these questions. F. Wichmann will give a general overview of how internal visual representations can be estimated. R. Johansson and P. Kelber will present recent work on time perception: R. Johansson will discuss time and intensity judgements, and P. Kelber will present boundary conditions for visual duration discrimination. D. Oberfeld-Twistel will discuss how biases observed in pedestrians' arrival time estimation for approaching vehicles can be captured by a Bayesian observer model. Finally, K. Bhatia will ask what we can learn from visual size discrimination about the cognitive representations underlying the visual guidance of perception and action.
Submission 143
Internal Reference Updating in Visual Duration Discrimination: A Search for Boundary Conditions
SymposiumTalk-04
Presented by: Paul Kelber
Paul Kelber 1, Rolf Ulrich 1, Karin Maria Bausenhart 1, Roman Liepelt 2, Ruben Ellinghaus 2
1 University of Tübingen, Germany
2 University of Hagen, Germany
A growing body of psychophysical research suggests that the comparative judgment of successive stimuli involves more than taking the difference between their sensation magnitudes, challenging traditional difference models, such as signal detection theory. Two elaborated theories assume that each sensation magnitude is weighted by its reference level (sensation weighting model) or that the second sensation magnitude is compared to a dynamically updated internal reference, in which the first sensation magnitude gravitates towards the previous reference level (internal reference model). Whereas both models can explain higher discrimination sensitivity when the standard precedes the comparison (negative Type B effect), only the sensation weighting model can account for higher discrimination sensitivity when the standard follows the comparison (positive Type B effect). Most previous studies reported negative Type B effects, while some positive Type B effects have also been reported, especially for duration discrimination with short stimulus durations and/or short inter-stimulus intervals combined with adaptive-staircase procedures. The presented study systematically searched for positive Type B effects in visual duration discrimination by orthogonally varying stimulus duration (80 versus 500 ms standard), inter-stimulus interval (200 versus 900 ms), and stimulus type (filled versus empty intervals) across four experiments (plus one pilot experiment) using the method of constant stimuli. Type B effects were consistently negative across all experimental conditions and analysis methods. This overall absence of positive Type B effects in visual duration discrimination questions the need for the flexible sensation weighting framework and supports more parsimonious theories of comparative judgment, such as the internal reference model.